_Rudolf Hilferding_, a Viennese like the rest, entered the German Social-Democratic Party almost as a mutineer, but as a mutineer of the Austrian stamp, _i.e._, always ready to capitulate without a fight. Hilferding took the external mobility and bustle of the Austrian policy which brought him up for revolutionary initiative; and for a round dozen of months he demanded--true, in the most moderate terms--a more intelligent policy on the part of the leaders of the German Social-Democracy. But the Austro-Viennese bustle swiftly disappeared from his own nature. He soon became subjected to the mechanical rhythm of Berlin and the automatic spiritual life of the German Social-Democracy. He devoted his intellectual energy to the purely theoretical sphere, where he did not say a great deal, true--no Austro-Marxist has ever said a great deal in any sphere--but in which he did, at any rate, write a serious book. With this book on his back, like a porter with a heavy load, he entered the revolutionary epoch. But the most scientific book cannot replace the absence of will, of initiative, of revolutionary instinct and political decision, without which action is inconceivable. A doctor by training, Hilferding is inclined to sobriety, and, in spite of his theoretical education, he represents the most primitive type of empiricist in questions of policy. The chief problem of to-day is for him not to leave the lines laid down for him by yesterday, and to find for this conservative and bourgeois apathy a scientific, economic explanation. _Friedrich Adler_ is the most balanced representative of the Austro-Marxian type. He has inherited from his father the latter's political temperament. In the petty exhausting struggle with the disorder of Austrian conditions, Friedrich Adler allowed his ironical scepticism finally to destroy the revolutionary foundations of his world outlook. The temperament inherited from his father more than once drove him into opposition to the school created by his father. At certain moments Friedrich Adler might seem the very revolutionary negation of the Austrian school. In reality, he was and remains its necessary coping-stone. His explosive revolutionism foreshadowed acute attacks of despair amidst Austrian opportunism, which from time to time became terrified at its own insignificance. Friedrich Adler is a sceptic from head to foot: he does not believe in the masses, or in their capacity for action. At the time when Karl Liebknecht, in the hour of supreme triumph of German militarism, went out to the Potsdamerplatz to call the oppressed masses to the open struggle, Friedrich Adler went into a bourgeois restaurant to assassinate there the Austrian Premier. By his solitary shot, Friedrich Adler vainly attempted to put an end to his own scepticism. After that hysterical strain, he fell into still more complete prostration.